Transmission device

Abstract

Provided is a transmission device that can increase a lubricity of a bearing in a planetary gear. The present disclosure includes the transmission device including a sun gear, a ring gear, planetary gears, bearings through shafts of the planetary gears are inserted, a differential case including bearing holders holding the respective bearings, a differential mechanism arranged inside the differential case, and a gear case supporting the differential case in a rotatable manner. Each bearing holder includes a cylindrical part holding a corresponding one of the bearings, and a pocket that is recessed from a radially inner side to a radially outer side to have an internal space that axially overlaps with the corresponding one of the bearings. The gear case includes a protrusion that is arranged to overlap with the pockets from the radially inner side of the sun gear and that axially protrudes toward the bearings.

1 . A transmission device, comprising:
 a sun gear;   a ring gear arranged concentrically with the sun gear;   planetary gears meshing with the sun gear and with the ring gear;   bearings through each of which a shaft of a corresponding one of the planetary gears is inserted;   a differential case including bearing holders each holding a corresponding one of the bearings;   a differential mechanism arranged inside the differential case;   a first output shaft and a second output shaft that are coupled to the differential mechanism; and   a gear case supporting the differential case in a rotatable manner, wherein the bearing holders each include:
 a cylindrical part holding a corresponding one of the bearings, and 
 a pocket that is recessed from a radially inner side toward a radially outer side of the sun gear to have an internal space and that overlaps with the corresponding one of the bearings in an axial direction of the sun gear, and 
   the gear case includes a protrusion that is arranged to overlap with the pocket of each bearing holder from the radially inner side of the sun gear and that protrudes toward the bearings in the axial direction of the sun gear.   
     
     
         2 . The transmission device according to  claim 1 , wherein
 the gear case further includes an inclined surface inclined, toward the protrusion, from a position that is farther from each bearing than the protrusion in the axial direction of the sun gear and that is on an inner side relative to the protrusion in a radial direction of the sun gear.   
     
     
         3 . The transmission device according to  claim 1 , wherein
 the gear case further includes a recess that is arranged in a back surface of the protrusion on the radially outer side of the sun gear and that is recessed toward the radially inner side of the sun gear.   
     
     
         4 . The transmission device according to  claim 1 , wherein
 the cylindrical part and the pocket are integral with each other.